THE EFFECT OF FUEL TO OXYGEN RATIOS ON THE PROPERTIES OF HIGH VELOCITY OXY-FUEL TiO2 NANO-PHOTOCATALYST COATINGS

2010 ◽  
Vol 24 (02) ◽  
pp. 247-255 ◽  
Author(s):  
MARYAMOSSADAT BOZORGTABAR ◽  
MEHDI SALEHI ◽  
MOHAMMADREZA RAHIMIPOUR ◽  
MOHAMMADREZA JAFARPOUR
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
High Velocity ◽  
X Ray Diffraction ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Transmission Electron ◽  
Hvof Thermal Spray ◽  
Coating Morphology ◽  
Oxygen Ratio

A liquid fuel high velocity oxy-fuel (HVOF) thermal spray process has been used to deposit TiO 2 photocatalytic coatings utilizing a commercially available anatase/rutile nano-powder as the feedstock. The coatings were characterized in terms of the phases present, its crystallite size and coating morphology by means of X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy, respectively. The results indicate that the sprayed TiO 2 coatings were composed of both TiO 2 phases, namely anatase and rutile with different phase content and crystallite size. A high anatase content of 80% by volume was achieved at 0.00015 fuel to oxygen ratio with nanostructure coating by grain size smaller than feedstock powder. It is found that fuel to oxygen ratio strongly influenced on temperature and velocity of particles in stream jet consequently on phase transformation of anatase to rutile and their crystallite size and by optimizing the ratio which can promote structural transformation and grain coarsening in coating.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

Microstructural characteristics and photoluminescence performance of nanograined thermally treated CeO2-TiO2 xerogels

2007 ◽  
Vol 22 (5) ◽  
pp. 1182-1187
Author(s):  
Amita Verma ◽  
A.K. Srivastava ◽  
N. Karar ◽  
Harish Chander ◽  
S.A. Agnihotry
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
Sol Gel ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Crystallite Sizes ◽  
Thermally Treated

Nanostructured thermally treated xerogels have been synthesized using a sol-gel process involving cerium (Ce) chloride heptahydrate and titanium (Ti) propoxide mixed in different Ce:Ti molar ratios. Structural features of the xerogels have been correlated with their photoluminescence (PL) response. The crystallite sizes in the samples lie in the nanorange. The x-ray diffraction and transmission electron microscopy results have confirmed the coexistence of CeO2 and TiO2 nanocrystallites in these xerogels. In general, a decrease in the CeO2 crystallite size and an increase in the TiO2 crystallite size are observed in the xerogels as a function of Ti content. Scanning electron microscopy results have evidenced the evolution of ordered structure in the xerogels as a function of TiO2 content. Although both of the phases (CeO2 and TiO2) have exhibited PL in ultraviolet and visible regions, the major luminescence contribution has been made by the CeO2 phase. The largest sized CeO2 crystallites in 1:1 thermally treated xerogel have led to its highest PL response. PL emission in the xerogels is assigned to their nanocrystalline nature and oxygen vacancy-related defects.

Microstructure and Hardness Characterization of a NiCr/Cr3C2 Coating by High-Velocity Oxy-Fuel Thermal Spraying

2009 ◽  
Vol 79-82 ◽  
pp. 397-400
Author(s):  
Yu Ping Wu ◽  
Gai Ye Li
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
High Velocity ◽  
Steel Substrate ◽  
Thermal Spraying ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hvof Thermal Spraying

A NiCr/Cr3C2 composite coating with a thickness of approximately 200 m was deposited onto 1Cr18Ni9Ti stainless steel substrate by high-velocity oxy-fuel (HVOF) thermal spraying. Microstructure of the coating was characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscopy (TEM). The coating comprised a NiCr matrix and two types of carbides. The NiCr matrix was composed of an amorphous phase and nanocrystalline grain with a size of 10–50 nm. The microhardness of the coating was found to be 1200Hv, which is significantly greater than that of the stainless steel (1Cr18Ni9Ti) substrate (285 Hv).

Preparation of Nanostructured Al-4.5wt%Mg Powder via Mechanical Alloying Process

2011 ◽  
Vol 13 ◽  
pp. 1-5 ◽  
Author(s):  
Ali Shokuhfar ◽  
Omid Ozhdelnia ◽  
Ali Mostaed ◽  
Ehsan Mostaed
Keyword(s):  
Electron Microscopy ◽  
Mechanical Alloying ◽  
Crystallite Size ◽  
Weight Ratio ◽  
Milled Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Ma Process ◽  
Xrd And Tem

In this work, the preparation of nanostructured Al-4.5wt%Mg powder through the mechanical alloying (MA) process was evaluated. The X-ray diffraction (XRD) technique was used to calculate the crystallite size and microstrain. Scanning electron microscopy (SEM) was used not only to study the morphology of the powders but also to show the fact that the Mg powders were distributed during the MA process. Transmission electron microscopy (TEM) was also used to demonstrate whether the produced powders are nanostructured or not. XRD results showed that microstrain and crystallite size of milled powder (after 10 h milling at the ball-to-powder weight ratio (BPR) of 20:1) were ≈-0.34% and ≈20nm respectively. XRD and TEM results showed that Al12Mg17has been formed during MA process. This means that during this process, mutual diffusion of Al and Mg has occurred.

scholarly journals Effect of Pr, Sm, and Tb Doping on the Morphology, Crystallite Size, and N2O Decomposition Activity of Co3O4Nanorods

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Bahaa M. Abu-Zied ◽  
Salem M. Bawaked ◽  
Samia A. Kosa ◽  
Wilhelm Schwieger
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
N2o Decomposition ◽  
Direct Decomposition ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Subsequent Calcination ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Decomposition Pathway

Cobalt(II,III) oxide, Co3O4, is a promising catalyst for nitrous oxide direct decomposition. In this paper we report effect of doping with some rare earth (RE) elements (Pr, Sm, and Tb) on the morphology and crystallite size of Co3O4nanorods. The various precursors (RE/Co oxalates) were prepared via the microwave assisted method and subsequent calcination. The decomposition pathway of these precursors was followed using thermogravimetric analysis (TGA). Based on thermal analysis results, Pr-, Sm-, and Tb-doped Co3O4samples were obtained via the calcination in static air at 500°C for their oxalate precursors. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and hydrogen temperature programmed reduction (H2-TPR) were used to characterize the RE-doped cobalt oxide catalysts. The activity of the prepared catalysts was investigated for N2O direct decomposition and compared with that of the undoped Co3O4catalyst. It was shown that the promoted Co3O4catalysts revealed higher activity compared to the unpromoted one. The dependence of the activity on both the catalysts particle size and the reduction behaviour was discussed.

scholarly journals Síntesis de Puntos Cuánticos de SnO2 por Precipitación Química Asistida con Radiación Ultrasónica

2018 ◽  
pp. 97-101
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Crystallite Size ◽  
Chemical Precipitation ◽  
Ultrasonic Waves ◽  
X Ray Diffraction ◽  
Rutile Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy

Síntesis de Puntos Cuánticos de SnO2 por Precipitación Química Asistida con Radiación Ultrasónica P. Alvarado1, D. Acosta2, M.M. Gomez1, J.L. Solis1,2 1 Facultad de Ciencias, Universidad Nacional de Ingeniería, Lima 25, Perú 2 Laboratorio de Películas Delgadas, Instituto de Física, UNAM, Circuito de la Investigación Científica, Ciudad Universitaria, C.P. 04510, México Recibido 8 de noviembre del 2018, Revisado el 10 de diciembre de 2018. Aceptado el 12 de diciembre de 2018 DOI: https://doi.org/10.33017/RevECIPeru2018.0015/ Resumen Puntos cuánticos de SnO2 fueron preparados vía precipitación química asistida con ondas ultrasonicas. Análisis de difracción de rayos (XRD) confirmaron la estructura tetragonal tipo rutilo de los puntos cuánticos de SnO2 con tamaño de cristalito de 1,4 nm. Las micrografías de microscopia electrónica de barrido (SEM) de la muestra en polvo obtenida muestra que los puntos cuánticos de SnO2 son partículas aglomeradas alrededor de 10 nm, mientras las imágenes de microscopia electrónica de transmisión (TEM) confirman que el tamaño del cristalito es similar a la medición realizada por difracción de rayos X (XRD). El ancho de banda de energía de los puntos cuánticos de SnO2 medida por espectroscopia UV Vis de reflexión difusa fue de 4.3 eV, mostrando un significativo desplazamiento atribuido al confinamiento cuántico. Descriptores: Puntos cuánticos, ultrasónicos. Abstract SnO2 quantum dots were prepared via chemical precipitation assisted with ultrasonic waves. X-ray diffraction analysis (XRD) confirmed the tetragonal rutile structure of quantum dots SnO2 with crystallite size of 1.4 nm. The scanning electron microscopy (SEM) micrographs of the obtained powder sample show that the SnO2 quantum dots are agglomerated particles around 10 nm, while the transmission electron microscopy (TEM) images confirm that the crystallite size is similar to the measurement made by X-ray diffraction (XRD). The energy bandwidth of the quantum dots of SnO2 measured by UV Vis spectroscopy of diffuse reflection was 4.3 eV, showing a significant displacement attributed to the quantum confinement. Keywords: Quantum points, ultrasonic.

scholarly journals Direct Fabrication of Cobalt Oxide Nanoparticles Employing Sucrose as a Combustion Fuel

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
M. Th. Makhlouf ◽  
B. M. Abu-Zied ◽  
T. H. Mansoure
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Thermal Analyses ◽  
Combustion Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cobalt Oxide Nanoparticles ◽  
Transmission Electron

Combustion method has been used as a fast and facile method to prepare nanocrystalline Co3O4 spinel employing sucrose as a combustion fuel. The products were characterized by thermal analyses (TGA and DTA), X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Experimental results revealed that the molar ratio of fuel/oxidizer (F/O) plays an important role in controlling the crystallite size of Co3O4 nanoparticles. Transmission electron microscopy indicated that the crystallite size of Co3O4 nanocrystals was in the range of 13–32 nm. X-ray diffraction confirmed the formation of CoO phase with spinel Co3O4. The effect of calcination temperature on crystallite size and morphology has been, also, discussed.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Sign in / Sign up

Export Citation Format

Share Document